1. Field of the Invention
The present invention relates to a reverse-conducting thyristor such as is known, for example, from U.S. Pat. No. 4,150,391.
2. Discussion of Background
Reverse-conducting thyristors are understood to be integrated power semiconductors in which a thyristor structure and a diode structure are arranged next to each other on a common substrate in such a manner that the diode is electrically connected in antiparallel with the thyristor.
Such a thyristor is capable of accommodating blocking voltage only while it is short-circuited in the non-conducting direction by the antiparallel diode. Omission of a blocking p-n junction in the thyristor, connected with this, makes it possible to reduce the losses in the conducting direction and to reduce the circuit-commutated recovery time. The resultant advantages for application are described in detail, for example in Brown Boveri Review, Volume 66, No. 1, 1979, pages 5-10.
Although improvements have already been achieved with respect to the maximum switching frequency possible by integrating the antiparallel diode into a thyristor having the usual structure, it is, nevertheless, desirable to be able to switch at even higher frequencies, at powers which are at the same time high, as a result of which the range of applications of the reverse-conducting thyristor would be expanded.
It is also known that the so-called field-controlled thyristors (FCT), which have been described, for example, in European Patent application No. 0,121,068, are superior to the above-mentioned usual thyristors with respect to switching frequency.